1. Field of the Invention
The present invention relates to a photosensitive composition that can cause reaction and change a property thereof when irradiated with an actinic ray or radiation, to a compound used in such a photosensitive composition, and to a patterning method using such a photosensitive composition. More specifically, the invention is concerned with a photosensitive comp osition usable in a process of manufacturing semiconductors such as ICs, in production of circuit boards for liquid crystal displays or thermal heads, and what is more, in other photofabrication processes, lithographic printing plates and acid-curable compositions. And the invention further relates to a compound used in the aforesaid photosensitive composition, and to a patterning method using the aforesaid photosensitive composition.
2. Description of the Related Art
A chemical amplification resist composition is a patterning material that, when irradiated with radiation, such as far-ultraviolet light, produces an acid in the areas irradiated, utilizes the acid as a catalyst to cause reaction and makes a difference in developer solubility between irradiated and unirradiated areas, thereby enabling formation of patterns on a substrate.
When KrF excimer laser is used as an exposure light source, such a chemical amplification resist composition uses as a main component a resin whose basic skeleton is poly(hydroxystyrene) principally having small absorption in the region of 248 nm; as a result, patterns of good quality are formed at high sensitivity and high resolution. Therefore, this composition forms a good system compared with the traditional naphthoquinone diazide/novolak resin system.
When a light source of shorter wavelengths, e.g., ArF excimer laser (193 nm), is used as an exposure light source, on the other hand, even the foregoing chemical amplification system is not satisfactory because compounds having aromatic groups substantially exhibit great absorption in the region of 193 nm.
Therefore, resists containing resins of alicyclic hydrocarbon structures are being developed specifically for ArF excimer laser.
As to the acid generator as another main component of a chemical amplification resist composition, a wide variety of compounds have been found, and triarylsulfonium salts, arylalkylsulfonium salts (See, e.g., JP-A-2000-275845 and JP-A-10-48814), and sulfonium salts having thiophenine structures (See, e.g., WO 02/19033 pamphlet and WO 03/3120 pamphlet) are disclosed.
However, the chemical amplification resist compositions hitherto developed are still insufficient in many respects, and it is hoped that exposure latitude and line-edge roughness will be improved.